How about organized crime? Gambling, hit men, etc... you can even have organized crime factions.

Also, you should be able to transport weapons between stations and sell them to other players.

Also, in addition to station guards you can have stationary automatic weapons platforms guarding stations and wormholes.

Just rambling...

i've noticed that organized crime is taking form in a slow kinda way. This is something that needs to grow from the community imo, so, it's up to you, but watch out for the law (bountyhunters) ;)